Telephone repeater circuit and apparatus.



PATENTED NOV. 6, 1906.

H. E. SHREEVE. TELEPHONE REPEATERGIRGUIT AND APPARATUS.

APPLIOATION-FILED' JAN. 24. 1906.

' INVENTOR.

ATTORNEY.

E S S m W in the main-line sections, interfering with j UNI ED ,STATES' PATENT, OFFICE.

AMERICAN TELEPHONE AND T TIQN OF NEW YORK.

ELEGRAPH COMPANY,- A CORPORA TELEPHONE REPEATER ,CIRQUZIT AND APPARATUS.

. Specification of Letters'Patent. I Application filed January 24, 1906. Serial No. 297,630-

Patented Nov. 6, 1906.

To dll whom/ it may concern:

Be it known that I, HERBERT E. SHREEVE,

r residing'at Newton, in the county of Middlesex and State of Massachusetts, have invented certain Improvements in Telephone,

Repeater Circuits and Apparatus, of which the following is a specification.

This invention relates to systems for the reinforcement or renewal of currents employed in telephonic transmission, and more es ecially to means for balancing the circuits 11 systems in which a relay or re eater cir cuit is arranged similarly to a heatstone bridgesuch, for example, as that described in any Patent N o'. 791,656, dated June 6, j 1905-it is important that the electrical conditions in the main line upon opposite sides of said relay-circuit shall be substantially the same. If the imp'edence of the sections ofthe main-line circuit or independent lines constituting such av circuit is materially different, induced currents may flow in the bridge connection and produce a singing im the relay. Moreover, the difference in impedance tends to alter the phase of the currents transmission. p

The principal object of my invention is to provide means for so .balancing lines of different character and dimensions that these difiiculties may be overcome.

The invention consists, more essentially, in the inclusion "in a main-line telephone-circuit and associated with a bridged relayof means for altering the electrical conditions or properties by adjusting either the resistance or capacit of said circuit, the arrangement being suc that these agencies will most effect- .ively perform their functions.

,In the accom anying drawings, in which like characters esignate like parts throughout both -view's,-Figure1 shows diagrammatically one embodiment of my improved system, and Fig. 2 is a top plan view in diagram of a formpf induction-coil used in said system in ractice.

have in the present instance illustrated a metallic telephonic maineline'circuit extending between statio' AandB and having an intermediate station C. fThis stationO divides the line into sections L and L, which, as is commonly the case in practice,'are unbalanced, the impedance of the section L being considered the lower. At the station 0 is a current-reinforcing message-repeating or relay apparatus R, having its receiving element 1' situated in a bridgeconnection L extendin between opposite sides of the main line. he transmitting element 1' of said apparatus is included in a local circuit L, containing the primary winding pof a transmitting induction-coil P and a attery or like source of electrical energy V. ary ,wi ndin of the coil 1 is electrically -'divided lnto our sections 8, s s and 8, these sections being connected in pairs upon opposite sides of the bridge, and in such a manner that they no not themselves disturb the balance of the-line and so that the currents induced in them Will not oppose one another'in the main circuit or circuits. tion is similar to that described in the previously-mentioned patent. The repeating induction-coil there illustrated has, however, been omitted, though it may be used, if desired, in connection with the present invention.

Included in each side of the main-line circuit is an adjustable resistance, this being preferably in four sections w, w, w, and w,

s, 8 and s, respectively, of the inductioncoil P and the complementary end of the bridge connection Eachof these resistances preferably includes separated coils connected to contacts 10, over which is movable a lever 11, thus enabling a 'greater or less hne. H p

Bridged between the conductors of the condensers C and C, respectively, of variation to the two sections of the associated induction-coil secondary winding, each condenser being arranged in sections connected to circuit-changing plates 12, which may be 'oined by plugs 13 to alter the capacity.

hese condensers may be effectively laced at the opposite sides of the associate pairs of secondary windings from the relay. As shown, these condensers 'are bridged across pendently of both the relay apparatus at sta- This organizasituated between the secondary windings e,

main circuits or circuit-sections L and L are ble capacity, each in parallel or shunt rela-- The secondamount of resistance to be inserted in the the main circuit or circuit-sections indelar electrical conditions are attained by varying,.through either addition or subtraction, the resistance and capacity of either or both of said lines or line-sections until the most effective transmission in both directions is attained. To secure this result in the particu- 1o lar system illustrated,a suitable amount of these-agencies.

. well known resistance is thrown in by moving the levers of the resistances w 10 and capacity introduced by the application of one or more plugs to the circuitch'anger controlling the condenser C. This latter operation also permits the equalizing of the phase in the sections. If necessary, these adjustments may be readily altered to meet varying electrical properties or conditions of the line. It should be noticed that the placing of the resistances. and condensers at the points shown allows the balance of all portions of the main-line circuit with which is associated a reinforcing system of the character described without the'introduction of disturbing conditions by 4 While this invention has been described in connection with a continuous circuit having sections, it will be obvious that it is equally applicable to independent circuits organized and adapted to repeat into one another reciprocal y. L t Y The relay apparatus operates in a manner and need not be particularly referred to. I i

Though the induction-coil P for the sake of clearriess is shown diagrammatically in Fig. 1 as being in two independent portions, it will be evident that the windings may be about .a single core 14, as has been illustrated in Fig. 2, these windings leading to terminals 15, to

which the circuits are connected. An arrangementof this sort is the one usual in practice. r

Having thus descr bed my 111V611t1011,

, claim 1. In a system for the reinforcement or renewal'of telephone-currents, the combination ,with telephonic current-transmittingcir cuits' or circuit-sections, of atransmitting in- "ductio'n-coil situated at the juncture of the sections, a relay or reinforcing ap aratus as- :sociated with the induction-coil, grid means independent .of the induction-coil for adjust- 5' ,ing the relative resistance andcapacity of the circuits or circuit-sections." I

2. A system for the reinforcement or ren'ewal of telephone-currents comprising transmitting-circuit sections, an induction-coil sit- -=uated at the juncture of the circuit-sections, a reinforcing apparatus associated with the induction-coil, and means for varying the electrical properties of thecircui-t-sections,

the said means for-each circuit-section being connected with the said circuit-section to which it belongs, at one side only of the indriction-coil and reinforcing apparatus.

3. In a 'system for the reinforcement or renewal of telephone-currentathe combination with a circuit comprising sections offering difierent impedance, of an induction-coil having windings situated at each side of the circuit, a relay apparatus bridged across the circuit between the induction-coil windings, and a resistance included in the circuit between an induction-coil winding and the relay apparatus and serving to balance the impedance of the circuitsec-tions, substantially as described.

4. In a system for the reinforcement or renewal of telephone-currents, the combination with a circuit comprisin main circuits or circuit-sections, of a re ay apparatus bridged across the circuit at the juncture of the said circuits or circuit-sections, and an adjustable resistance included'in each side of the circuit and in series therewith upon opposite sides of the bridge.

.5. The combination with the telephonecircuit, of an induction-coil having e ectrically-divided windings situated in-each side of the circuit, a bridge connection across the able resistance included in the circuit between an induction-coil winding and the bridge connection.

6. The combination with the tele honecircuit, of an induction-coiL-having .e ectrically-divided windings situated in each side -of the circuit, a bridge connection across the circuit from points between the divisions of the induction-coil windings, a relay apparatus in thebridgeconnection, and an adj ustable resistance included in the circuit between each division .of the induction-coil winding and-the bridge connection.

7. In a system for the reinforcement -or renewal of telephone-currents, the com-bina I oo tion with a circuit comprising telephonic current-transmitting sections of dlifierentcapacity, of a relay apparatus associated with the circuit, and means connected with the circuit for balancing'the capacity .of its said sections. a I

8. In .a system for the reinforcement .or

renewal of telephone-currents, the combina tion with a circuit, of a bridge connection 7 across the circuit, a relay apparatus in the bridge connection, and .a condenser of adustable capacity bridged across the circuit independently of the relay apparatus and of the telephone apparatus.

9. The combination with the telephonecircuit, of an induction-coil, having e ectrically-divided windings situated in each side of the circuit, a bridge connection across the circuit from points between the divisions of the circuit, a bridge connection across the circuit from' points between the divisions each slit; of the brid e connection.

tion with a circuit, of abridge connection across the circuit, ,a' relay apparatusin the- IO. v in the circuit at each side of the bri conbridge connection, an adjustable resistance nection, and capacitymeans s unted across thecircuit, substant y as set forth.

11. The combinationiwith the telephone circuit, of an induction-coil having electrically-divided windings situated in each side of 0f the induction-coil wind1ngs,'a relay ap aratus-in the bridge connection, an adjusta le resistance included in the circuit between an induction-coil and the bridge con-' S nectibn, and a condenser bri ed across the circuit independently of the re" ay ap aratus.

12. The combination with a met'aiii divided secondary winding, there a plurality of divisions at'each side of the circuit, a relay apparatus connected with the opposite sides of the circuit between the 0 each si e of the relay ap status.- In testimony whereoi name t0 this specification, in the presence of two subscribing witnesses, this 22d day of January, 1906. HERBERT E. SHREEVE.

witnessesz Y i G'Eo. WILLIS PIERCE,

{ Jos'nrn A. GATELY.

phone-circuit; of aninduction-coil having a able capacity bridged across the circuit at 5 -I have signed my 

